You heard it here first: these four defenders will bust out in '08.

By K.C. Joyner, The Football Scientist

Sleepers? Not exactly. More like Leonardo DiCaprio circa What's Eating Gilbert Grape. You immediately spotted greatness, but the rest of the world needed some time to recognize it. Each of these defensive players is 24 or younger, and all are on the cusp of that magical tipping point.

ELVIS DUMERVIL
DE, Broncos
At 5'11" and 260 pounds, Dumervil doesn't look like much. But his numbers—12.5 sacks in 2007, 8.5 as a rook, in '06—are ginormous. Though he's the only DE in the league under six feet, Dumervil dominates with multiple pass-rush moves and superior technique. Using a speed rush, he picked up four sacks via outside rip moves last year. But what makes the 24-year-old special is his bull rush, which requires equal amounts of power and technique. Dumervil got under the shoulder pads—naturally—to beat such behemoth's as Cornell Green (6'6", 315) and Jeff Backus (6'5", 305) for sacks last season.

TANARD JACKSON
S, Buccaneers
Big hits aside (see pic; sorry, Dallas Clark), the second-year pro is ready to blow up because of his coverage skills. Prior to Jackson, D-coordinator Monte Kiffin had used seven different starters at the coverage safety position since 1996. But if Jackson's 2007 deep-assist metrics are any indication, Kiffin can stop tinkering. Deep-assist plays are when the coverage safety helps a corner over the top, usually 20 to 30 yards downfield. Jackson made 12 deep-assist plays—breaking up 10 pass attempts—and he finished the season allowing 2.3 YPA, best in the league among coverage safeties.

FRED BENNETT
CB, Texans
To experts who say Dunta Robinson is the best corner in Houston, think again. Bennett is not only better than Robinson, the stats say he was the premier corner in the league last season. The 24-year-old Bennett, a fourth-round pick in 2007, actually had better metrics in his eight starts than any numbers Robinson has posted in his four-year career. Bennett's 4.7 overall YPA led the league among corners with 60-plus attempts, and opposing WRs gained only 67 total yards on the 24 combined medium, deep and bomb passes he faced. With pass-happy teams like the Steelers, Colts and Browns on Houston's sked in 2008, Bennett's name will be on everyone's lips.

ERNIE SIMS
LB, Lions
It's not his fault the Lions D can't get off the field; Detroit ranked dead last in total plays (1,087) and, subsequently, in total D (377.6 ypg) last year. The 23-year-old Sims led the Lions in tackles his first two seasons. At six feet, 225 pounds, and with 4.5 40 speed, he's a younger version of Bucs LB Derrick Brooks. Sims is as good as it gets on pursuit plays. Detroit opponents gained just 48 yards on 13 stretch/sweep plays with Sims at the point of attack. Left unblocked on 11 of those plays, he was a human vacuum, allowing a mere 24 yards. With second-round pick Jordon Dizon set to play MLB, Sims should face less resistance to the ballcarrier this season. Scary.

SAFETY SWITCH

Merril Hoge breaks down how to change positions without missing a beat.

Moving from cornerback to safety sounds easy, but in reality, it's not. Cardinals DB Antrel Rolle is making the transition after the team picked CB Dominique Rodgers-Cromartie in the first round of the draft.

While playing corner for three years in Arizona's scheme, Rolle was able to focus on one man or area of the field, giving him the least amount of responsibility in the secondary. Now he'll have to decipher opponents' formations and then signal changes to his teammates before each snap. That means more time in the film room breaking down individual and team tendencies. For example, if the Seahawks come out in a two-tight-end set, Rolle must know the down and distance, as well as the likelihood that Seattle will use play-action or dump off to an RB.

Although the 25-year-old Rolle has good size (six feet, 208 pounds), he'll be in on roughly 15 more plays per game at safety, which means he'll take a pounding. By comparison, Carnell Lake, my former Steelers teammate, once told me that switching from safety to CB added several years to his career.

On the flip side, Rolle was a solid cover guy as a starting corner. At safety, matched up against TEs, RBs or a team's third WR, he'll shine. And when D-coordinator Clancy Pendergast goes to a nickle package, the Cardinals will gain an edge by having three CBs on the field.